a highly experienced climber like you doesnt even know how to give soft catches ???

Who said I don't know how to dynamic belay? What I'm arguing here are the exaggerated benefits.

bearbreeder wrote:

good thing you arent belaying me ... because id hate to get SLAMMED into the wall just because someone doesnt know how to catch sport whippers over and over again ... and is too "proud" to admit it

Sport whippers!? Isn't that an oxymoron?

if you took a 5-10+ whippers a day, 2-3 times a week, 52 weeks a year ... you wouldnt think they were exaggerated

all it takes is one hard catch that tweaks your ankle to realize this ... of your friend getting slammed by someone who didnt understand the concept, and not being able to climb for a year because of someones ignorance ...

Those graphs show quite clearly that the difference between dynamic and a simple belay is negligible.

Also all the comment regarding sport climbing and stopping the pendulum effect miss the point. A dynamic belay is not the best solution to avoiding a pendulum! The best solution is allowing more slack!

The "evidence" used to argue the opposite has simply been people bragging about their whippers.

jt512 wrote:

You are never belaying me.

Who said I had offered? Besides you continue to confuse technical discussion with actual belay techniques.

The real world is quite varied. If you can't think and alter your behaviour to the present situation then you may end up in an unsafe situation.

As I found out earlier in the week, even something as simple as a fireman's belay can be difficult and ineffective if somebody simply relies on rote technique.

patto wrote:

Syd wrote:

The main peak load occurs over 85ms (that is, the width of the peak above the final base load). The most extreme part of the peak load happens in a shorter period. It is interesting to consider this in relation to active dynamic belaying. It is claimed that if the belayer jumps or steps or actively initiates a moves in some way, when a climber falls, he can reduce the peak loading on the climber. It takes an absolute minimum of 200ms for a person to react to some stimulus (such as hearing a yell "falling" or seeing a fall), and generally this time is much longer. Further time is then required for the belayer to flex in some way. To reduce the peak load on the climber, the belayer's jump would then have to be precisely synchronised with the 85ms peak load. To me, this seems almost impossible.

Any "dynamic" effect by the belayer is simply the belayer being lifted off the ground by the impact of the fall. It is virtually impossible for the belayer to actively contribute to any impact reduction.

Many people consider that dynamic belaying is an essential part of good belaying but actions other than allowing some rope slip through the belay device at the moment of impact and an indirect or semi direct belay, seem futile.

I completely agree with this.

And I believe there has been other good research to support this. Dynamic belaying was found produce only very minor reductions in peak load. If you are doing it to make you and you partner more comfortable on repeated sport climbing falls then I don't see a problem. In steep over hangs more slack or dynamic belays can avoid ankle damaging pendulums.

If you think it is an essential part of safety in TRAD climbing then you are misguided. The difference between a grigri and a ATC is far bigger. But unless you are frequently leading very tiny pieces then I don't believe dynamic belays are important. (Even when I've lead X rated climbes with RPs and ultra micro cams I've never felt the need for a dynamic belay. Personally I want a reliable catch and in the event of piece failure a reliable FF2 preventative measures.)

Certainly amongst MY local TRAD community dynamic belays are never emphasised.

Except your agreement is based on completely flawed theory by Syd. Your "reason" refers to some "evidence" that the reduction is minimal. Care to provide it? Evidence provide here through actual testing and theoretical calculations shows significant decrease in both peak loads and pendulum velocity. Yet you are going to keep sticking by your vague "reason" with "evidence" that isn't to be seen? Are you being deliberately obtuse in your old age?

The "evidence" used to argue the opposite has simply been people bragging about their whippers. .

petzl, beal, ukclimbing, redpoint by the same authors of self coached climbing ...

thats just the start ...

go climb sport at your limit for a few months ... take the falls over and over again ... and youll see

let me ask you this ... how many whippers do ya catch in a day on 11+ sport routes, and how many falls a year ... i mean you are obviously so knowledgeable that you MUST have a massive amount of experience catching falls on hard sport climbs ...

an experienced belayer MUST have alot of experience catching falls ... they need to know WHEN to give a soft catch, when to sit right down, judge the effects of their catches on traverses and overhands, etc ... not just hold the rope and give a static belay ...

any belayer who doesnt have real world experience catching falls over and over again ... will be the one that gives you the wrong catch at the wrong time ... and youll get hurt

the person i WILL NOT climb with is the person who says "hey i will ignore everything from petzl, beal, and other sources because i dont believe dynamic belay works since i cant ADMIT im wrong .... who cares if you break your ankle since im ALWAYS RIGHT"

Those graphs show quite clearly that the difference between dynamic and a simple belay is negligible.

Also all the comment regarding sport climbing and stopping the pendulum effect miss the point. A dynamic belay is not the best solution to avoiding a pendulum! The best solution is allowing more slack!

You are never belaying me.

Jay

It is quite possible that I have partners who, without me being aware of it, are as inept as Patto. However, I don't have any that are as proud or as stubborn about their own failings. For that reason alone, Patto can add to me to the list of folks who will not climb with him.

the person i WILL NOT climb with is the person who says "hey i will ignore everything from petzl, beal, and other sources because i dont believe dynamic belay works since i cant ADMIT im wrong .... who cares if you break your ankle since im ALWAYS RIGHT"

Sigh.

Since my comments are being frequently misrepresented and twisted into something that is entirely different from what I have said I see no use in debating.

cracklover wrote:

It is quite possible that I have partners who, without me being aware of it, are as inept as Patto. However, I don't have any that are as proud or as stubborn about their own failings. For that reason alone, Patto can add to me to the list of folks who will not climb with him.

Having offensive people suggest the wont climb with my certainly isn't a problem for me!

However having people use this as a debating tool based on false interpretations of what I have said is a problem.

There is no use continuing when I'm continually being accused of saying things I have not.

in addition multiple posters who climb sport have told you that dynamic belaying is effective for preventing your climber from slamming into the wall ... yet you insist on going off about who knows what about how it ...

heres another one from "how to climb HARD TRAD" by britains best trad climber , dave macleod If there is enough height to manage it, get the belayer to give you a dynamic belay. This basically means the belayer slows the rate at which the rope comes tight, spreading the load out over time and lowering the peak forces on the gear. This is really effective both for preventing gear failing but also for lessening violent swings into the crag, which do cause some really bad injuries, even on apparently safe routes. There are a few techniques for dynamic belaying. The most obvious one is to let the rope run through the belay plate, gradually closing grip until the rope stops. In practice this is very difficult to do, so is best avoided for short routes. If you must use it, practice on some long sport routes first. The second is to belay slightly away from the crag and ‘run with’ the rope as it comes tight for a few steps. This might be a bad idea if the gear includes poor wires, where standing as close to the wall as possible is best. In this case, jump upwards with the rope as it comes tight, or use a bombproof runner close to the ground to redirect the rope.

but then i suppose you know better than him

as to "misconstrued" ... your the pot trying to call the kettle black

its quite obvious from this and other threads that some RCers dont understand, care or practice dynamic belays ... this is a serious hazard should you ever need to catch vertical to overhanging "clean" falls ... having your ankle or other extremity busted from slamming into the wall or other such that could be prevented with a dynamic belay is a VERY COMMON injury ....

and people say intraweb forums is a "good" place to learn basic safety advice

Dynamic belaying is a requirement for international competition climbing.

Prior to the event belayers are required to "Train in stopping a competitor's fall dynamically." (ISFC) or show they can belay dynamically (various national federations intepretation of this for selecting belayers.

During the event belayers are required to:- "Absorb the fall dynamically which is not synonymous to a long fall. Absorb the fall safely – sometimes a longer fall is needed in order to avoid hitting a roof edge, etc." (ISFC)

Well that should be easy considering not a single automatic or semi-automatic handheld belaying device exists, with the exception of roped soloing devices.[/quote

Halbautomat is widest used description of this kind of device in Europe and translates as semi-automatic. The IFSC is not part of the UIAA and don´t give a shit about whatever terminology they use this week, nor what you call them either.

Well that should be easy considering not a single automatic or semi-automatic handheld belaying device exists, with the exception of roped soloing devices.[/quote

Halbautomat is widest used description of this kind of device in Europe and translates as semi-automatic. The IFSC is not part of the UIAA and don´t give a shit about whatever terminology they use this week, nor what you call them either.

Since my comments are being frequently misrepresented and twisted into something that is entirely different from what I have said I see no use in debating.

cracklover wrote:

It is quite possible that I have partners who, without me being aware of it, are as inept as Patto. However, I don't have any that are as proud or as stubborn about their own failings. For that reason alone, Patto can add to me to the list of folks who will not climb with him.

Having offensive people suggest the wont climb with my certainly isn't a problem for me!

However having people use this as a debating tool based on false interpretations of what I have said is a problem.

There is no use continuing when I'm continually being accused of saying things I have not.

I'm sorry you find me to be offensive. If there's something I've said here that you find objectionable, please do point it out, and I'd be happy to address it, or, if I was in the wrong, apologize.

As for misrepresenting you, all I've said is that you seem to me to be both proud and stubborn about your method of belaying, which, unless I'm mistaken, is to give extra slack as opposed to a soft catch. You also have a variety of arguments, none of which are convincing to me, to back up this choice.

I've used the jump dynamic belay in a gym setting and the leaders involved have the impression of a softer catch. This corresponds to the extensive experience of the climbing community, as evidenced by the quotes from various sources posted by Bearbreeder and the IFSC regulations posted by Jim (English version of site at http://www.ifsc-climbing.org/). We have US Navy's test (one trial?), in which an 18% load reduction strikes me as better than one can expect in general, and the abstract of more extensive and probably more reliable testing by Walter Nachbauer posted by Magid, http://www.rockclimbing.com/...post=1899631#1899631 (the link there is broken and I haven't been able to find the paper), which observed a 12% reduction over a Munter hitch belay. Other reported results are very interesting---have a look!

The substantial experiential evidence and such tests as we have indicates that the millisecond arguments are wrong, probably because of assumptions that do not correspond to proper belay technique. The belayer has to be ready, standing with knees bent and a slight forward lean. The jump happens from this position as soon as rope tension is felt at the belay; there is no critical "timing" involved and it is not hard to get it right. Moreover, there is no danger of a premature jump (which could make for a very nasty catch), the worst outcome being loads no better than those from a standing belay.

These actions typically produce a catch that most leaders perceive as more comfortable. Whether this perception corresponds to a significant reduction in physical injuries is, as far as I know, unknown. We also don't know what physical aspects of the system, modified by the dynamic belay, contribute to the perception of a softer catch (which is to say that maybe we don't really know what a "soft catch" is). The studies tacitly assume that reduction in peak load is the governing parameter. With dynamic belaying, that reduction is associated with a lower rate of load increase (smaller maximum "jerk") on the way to the peak load. From a physiological point of view, I don't know which, if either, of these factors is more critical.

Almost every bit of research that has involved human belayers has noted a broad range of belayer reactions to identical stimuli, often broad enough to overwhelm the effects of the phenomena that were supposed to be tested. This being the case, it is reasonable to assume that belayer behavior with respect to dynamic belaying will be inconsistent, and so the importance of correct technique is to insure outcomes no worse than a standing belay.

Another issue for hard routes that involve multiple leader falls is that the rope gets progressively stiffer with each successive catch and so the impact forces rise on each successive fall, even with a dynamic belay. Those tweaked ankles could be a result of not switching ends after a few falls rather than whatever actions the belayer did or did not take. Old worn ropes will also be stiffer than less-used ones.

I think Patto is right to emphasize that issues associated with pendulums are not necessarily the same as the question of peak load reduction and that the discussion has been confused on this issue. Bearbreeder mentions dynamic belays in relation to "tweaked" ankles and some of the posts mention things like "smashing into the rock." This is usually a pendulum question, although a dynamic belay that plops the leader onto a ledge could also lead to injuries, and the ledge doesn't have to be very big if the wall is merely vertical. However, the typical scenario for a pendulum impact is a short fall on an overhanging wall. The leader pendulums in and smacks the wall hard, possibly injuring one or both ankles.

The problem here is that the small amount of rope out for a short fall determines, at the moment the pendulum begins, a relatively large initial angle and so relatively large amplitude---the leader "wants" to swing approximately as far to the other side of the pendulum point, but of course the wall is there to stop them. The solution to this problem, as Patto says, is lengthen the leader's fall. With more rope out, the pendulum effect engages with a smaller initial angle and so a smaller amplitude, and in addition the overhanging wall is moving away from the leader. The combined effect is that either the leader doesn't hit the wall at all while swinging, of if so hits with reduced horizontal velocity on the upward part of the pendulum motion.

The jump dynamic belay and the simple addition of slack to the belay both achieve this end. Adding slack to the belay increases the peak load, so is less desirable than the jump---assuming the belayer gets the jump right, and assuming that the three feet or so obtained from the jump is enough extra slack to produce a suitable reduction in the pendulum. These assumptions indicate that there is uncertainty that cannot be removed in any practical situation.

I think the uncertainty about the value of this process increases as the wall becomes less overhanging. Climbers, consciously, unconsciously, or because of the dynamics of the moment of release, end up falling way from vertical walls and so are subject to pendulum impacts when they swing back in. The biggest advantage in the overhanging case, that the wall is moving away from the climber, is no longer present, and the climber is going to hit the wall with some horizontal velocity from the pendulum effect no matter what. Moreover, as mentioned above, relatively small features on a vertical wall can do a lot of damage if the fall is lengthened and the climber hits them. All of this makes dynamic belaying a much iffier proposition.

I'd be particularly concerned when the belayer is lifted many feet. Tests by the CAI (which did not, however, involve a jump by the belayer) suggested that lifting the belay more than about 8 inches had no further effect on reducing the peak load to the top pro. Belayer lifts of ten feet have been mentioned in this thread (with an implication that the belayer is somehow able to decide on or control how much lift occurs). At some point the dangers associated with the climber hitting something (including the ground) and/or a midair collision of climber and belayer are going to seriously outweigh any advantages of letting that much extra slack run through the system. In this regard, it is important not to automatically equate lifting with load reduction or even with energy absorbtion. In the absence of friction, such a system would attain equilibrium in the form of motion at constant velocity, at which point any further lifting is of no value whatsoever.

In all these situations, the pendulum effect is not particularly great for long falls, and in addition the effects of jumping, both in terms of activating an alternative energy-absorbing mechanism and adding extra rope, will be negligible. It would be nice to have some idea when the effects of jumping really no longer have any useful effect, but meanwhile it is a technique primarily of value for relatively short falls, which are after all the primary type of fall for most sport climbing.

It is important to emphasize that the technique of standing away from the wall and moving towards when the rope tension is felt is, by and large, a sport-climbing technique. The same technique applied in the presence of trad gear risks zippering the pro from the ground up unless a genuinely bombproof directional anchor has been set up as the first piece.

and if a person believe that all they need to do is "give slack" you can still slam a lighter climber into the wall if its slightly slabby to slightly overhangingif you happen to give a very static (fight the fall by sitting back) belay at the moment the rope comes taut .... yes ive seen injuries from that as well

note that most the souces i posted including petzl, ukclimbing, doug hunter/dan hague, the UIAA link jim posted ... as well as all the people here who sport climb alot ... say or imply that simply giving slack isnt the answer ...